Volt and ampere meter.



- Patented Dot. 10,1899.

J. D. RUSS.

VULT AND 'AIPEBE METER. (Application filed. Feb. Ia, 1599.

(No Nodal.)

WITNESSES: I V INVENTOI? i ATTORNEYS.

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UNITED STATES PATENT OF ICE.

JAMES D. ROSS, OF VICTORIA, CANADA.

VOLT AND AM PERE METER.

SPECIFICATION forming part of Letters Patent No. 634,767, dated October 10, 1899. Application filed February 18, 18599. Serial No. 706,003. (No model.)

To (ZZZ whom it may concern..-

Be it known that I, J AMES D. Ross, of Victoria, in the Province of British Columbia and Dominion of Canada, have invented a new and Improved Volt and Ampere Meter, of which the following is a fu'lLclear, and exact description.

This invention relates to improvements in volt and ampere meters; and the object is to provide a meter of simple and comparatively inexpensive construction, not liable to get out of order, and not aflected by heat or atmospheric changes.

I will describe a volt and ampere meter embodying my invention, and then point out the novel features in the appended claims.

Reference is to be had to the accompanying drawings, forming a part of this specification,

in which similar characters of reference indi cate corresponding parts in all the figures.

Figure 1 is a sectional elevation of a meter embodying my improvement. Fig. 2 is a sectional elevation showing a modification, and

Fig. 3 is a-section showing another modifica-' tion.

Referring first'to the example of my improvement shown in Fig. 1, 1.2 designate two casings or shellsforming air-chambers. These" casings or shells have equal air-containing capacity, and they are connected one with the other bymeans of a capillary tube 3, having vertically-disposed members and a cross-connection at the bottom, and in this tube is arranged a liquid column 4, consisting of spirits ,of mercury. Extended into one of the cylinders or shells (here shown as cylinder or shell 1) is a resistance-coil 5, which has its termiless resistance, I attach it to a removable cover 9 on the cylinder or casing 1.

fore stated, the two cylinders or casings must have an equal containing capacity, so that in a normal condition or when no current is flowing through the resistance 5, the pressure will be equalized in the two cylinders or casings. In orderto provide for a minute adjustment or equalization of the pressure, I provide the cyl- As beor chambers.

inder or casing 2 with a flexible top 10, which is engaged by an adjusting-screw '11, having a screw-thread engagement in a yoke 12.

On the branch of the pipe 3 which leads into the cylinder or casing 2 or adjacent to said branch is a scale 13,"marked inelectrical units or their fractions. The resistance 5 is of a coarseness depending upon the relative sizes of the cylinders or casings and the tube and the current to be measured. It is connected across mains or in the circuit according as it is used as a voltmeter orampere meter, and it may carry all the current or be used in shunt, as desired. In operation if a current traverses the resistance 5 it heats the air confined in the cylinder or casing 1 and the expansion of said air forces the liquid column 4 upward in the branch of the tube connecting with the cylinderor casing 2, and the greater the current the greater the heat and consequent expansion, so that the upper end of the column will indicate on the scale the pressure or the current, as the case may be. In the example of my improvement shown in Fig. 2 the construction is similar to that above described in connection with Fig. 1, excepting that in the cylinder or casing 2 a resistance or conductor 14 is also placed. This arrangement of the device may be employed for making comparisons between two currents of electricity. arranged adjacent to the sect-ion of the tube 3, connecting with the shell or casing 1, so that by noting the height of. the mercury column on the two scales the difference of inten sity of the. two currents may be observed.

In'the example of my improvement shown in Fig. 3 there are two shells or casings 15 16,

j-which, like the shells orcasingsfirst described, are. air-tight and of equal internal capacity. In one of the shells or casings (here shown as the shell or casing15) is the couductor or resistance 17, and the outer end of the shell or casing 16 ismade flexible and is engaged by a screw 18 for the purpose of equalizing the pressure in the two cylinders The inner or adjacent ends of the two cylinders or casings 15 and 16 are movable inward and outward relatively to the shells-or casings. As here shown, the adjacent ends of the shells or casings 15 and 1G In this example a scale 13 is are made in the form of fiexible disks or diaphragms l9 and 20, and they are connected at the center by a rod 21,

In the first example of my improvement I have shown the indicator as consisting of a liquid column. In thisinstance, however, the indicator consists of a pointer 22, having swinging connection with the rod 2L and having pivotal connection with a fixed stud 23. The end of this indicator 22 is movable over a scale 24, marked-with the electrical units.

Obviously the operation of the device shown in Fig. 3 will be substantially the same as before describedthat.is, the increase of pressure caused by a current flowing through the conductor 17 will operate the adjacent movable ends of the cylinders or casings against the air-resistance in the cylinder or casing 16, and consequently moving the indicator or pointerQO along the scale.

Having thus fullydescribed my invention, I claim as new and desire to secure by Letters Patent- 7 1. In an electric meter, two air-tight cylinders, a capillary tube connecting the two cylinders, a liquid in said tube, a gage having fixed relation with the tube, and means for 3. An electric meter, comprising two airconnected by a tube containing a liquid column, means for equalizing the initial pressure in the casings and an electric conductor extended into one of the cylinders or casings, substantially as specified.

5. An electric meter, comprising two airtight cylinders or casings of equal internal capacity, means forequalizing the initial pressure in the two cylinders, a tube connecting the two cylinders or casings and containing a liquid, a scale, and a resistance extended into one of the cylinders or casings and adapted for connection with an electric conductor, substantially as specified.

6. In an electric meter, two air-tight cylinders of equal interior capacity, a capillary tube connecting the two cylinders, a liquid in said tube, a conductor arranged in one of the cylinders, and means for equalizing the initial pressure in the two cylinders, substantially as specified.

JAMES ROSS.

Witnesses:

EDWIN A. BRADLEY, GEORGE N. GOWEN. 

